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Introduction to Food Safety and Microbiology

11Lecture 3Food Safety Divided into causitive categories called hazardsBiological Hazards - bacteria, molds, natural occurring toxinsChemical Hazards chemicals like petroleum, herbicides, pesticides, heavy metals. Physical Hazards glass, rocks, wood splinters21990 vs 19973

Lecture 2The good ole days were not that good.In 1900 tuberculoisis ; Pneumonia. Diaherra (food poisoning ) unheard of today. We prevent and or cure.As a percentage cancer and heart disease are increasing due to the decrease of other causes.Maybe the idea that cancer and heart disease increase due to chemicals in the food or environmental causes is way over played. Maybe the fact we are living longer . Longivity in 1900 was 46, now 78 years. Henry Seideman Typhoid pneumonia

Never get past 100 years oldWhenever I hear cancer checkups saves lives wrong delayed the death but not saved.Glenn Beck everyone who has ever eaten carrots will eventaully die If we did too many people3Lecture 2Food Microbiology

4DefinitionMicroorganisms: Organisms such as bacteria, parasites, viruses, yeasts, and moldsUsually too small to be seen by the naked eye5

Definitions

Microorganisms: Organisms such as bacteria, parasites, viruses, yeasts, and moldsUsually too small to be seen by the naked eye

Lecture 356

Where are microorganisms?Soil & WaterPlants/ProductsUtensils/EquipmentGastrointestinal TractFood HandlersAnimal FeedsAnimal HidesAir & DustEVERYWHERE!

Where are microorganisms?

Soil & WaterPlants/ProductsUtensils/EquipmentGastrointestinal TractFood HandlersAnimal FeedsAnimal HidesAir & DustEVERYWHERE!

Lecture 378

Microorganisms in FoodMicroorganisms are important in many different ways: Pathogenic, or disease causing, microorganisms can cause illness Spoilage microorganisms cause a food to smell, taste, and look unacceptable Fermentation microorganisms produce a desired food product Other microorganisms do nothing in foods 9Microorganisms in Food

Naturally occurring vs. contaminationBeneficial microorganismsControlled fermentationsDetrimental microorganismsSpoilage organismsPathogens

Lecture 39Bacterial ClassificationsBacteria can be classified in a number of ways. *Their shape-Round=cocci; Elongated=rods

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Bacterial Classifications

Bacteria can be classified in a number of ways. *Their shape-Round=cocci Elongated=rods *Sporeforming; Some rod shaped bacteria are sporeformers. This is a dormant stage in their life cycle. These spores have the ability to survive a wide range of environmental extremes. They can survive heating up to 2120F and are resistant to most chemicals including sanitizing solutions. The most noteworthy sporeformer is Clostridium botulinum.

Lecture 310SporesSporeforming; Some rod shaped bacteria are sporeformers. This is a dormant stage in their life cycle. These spores have the ability to survive a wide range of environmental extremes. They can survive heating up to 2120F and are resistant to most chemicals including sanitizing solutions. The most noteworthy sporeformer is Clostridium botulinum.

Spores dormant stateMuch more resistant to environmental stresses (heat, cold, chemicals)Vegetative state active stateMore susceptible to inactivation

11Spores

Spores dormant stateMuch more resistant to environmental stresses (heat, cold, chemicals)Vegetative state active stateMore susceptible to inactivation

Lecture 311 12

PSYCHROPHILE: Grow from 1-20oCEXAMPLES: Pseudomonas, Flavobacterium, Alcaligenes

PSYCHROTROPHIC:Grow best at 37oC, but can grow at refrigeration (3-7oC)EXAMPLE: Listeria monocytogenes

MESOPHILE:Optimum temperature 20-40oCGroup containing most human pathogensEXAMPLES: E. coli, Salmonella, Clostridium botulinum

THERMOPHILE:Optimum temp >45oCEXAMPLE: Bacillus stearothermophilus

Temperature and Growth 13Low Temperatures Refrigeration (40-45oF) slows or stops bacterial growth Freezing stops bacterial growth

High Temperatures Heating (165oF or higher) destroys bacteria for immediate service foods served in restaurants and homes. Thermal processing of shelf stable foods (180 - 250oF) destroys bacteria for longer shelf-life foods temperature dependent upon product acidity Low acid canned foods inactivation of C. botulinum

Low and High Temperatures 14Reproduction of Bacterial Cells Reproduced by division Referred to as growth Under optimum conditions a cell divides every 20-30 minutes

Growth of BacteriaBinary Fission15Growth of Bacteria

Binary FissionLecture 315Controlling GrowthF FoodA AcidityT TemperatureT TimeO OxygenM Moisture

16Controlling Growth

F FoodA AcidityT TemperatureT TimeO OxygenM Moisture

Lecture 316Controlling GrowthFood Nutrients ContentFor growth, microorganisms require the following:WaterSource of energySource of nitrogenVitamins & related growth factorsMinerals

1717A lot of times there isnt much you can do to change the nutrient content of your food, but you should be aware of what nutrients are in your food and the extent to which they support microbial growth. For example, a product like ground beef has all of the above nutrients and would support microbial growth more readily than a product like lemonade that may only have carbohydrates and some vitamins and mineralsLecture 3 18 Optimal pH for growth: 6.0 8.0 Disease causing bacteria: 4.6 - 9.5 Spoilage bacteria: 1.5 - 9.5 Food Acidity 04.6147acidicbasicneutralpH Growth Range in Foods pH 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Vibrio spp.Campylobacter spp.MoldsYeastsLactic Acid BacteriaStaphylococcus aureusSalmonella spp.Escherichia coliSource: Jay, J.M. 1996. Modern Food Microbiology19pH Growth Range in Foods

Lecture 31920

20Lecture 11Controlling GrowthT =TemperatureOptimal GrowthThermophiles like hot conditionsMesophiles like warm conditions (around body temperature)Psychrotrophs can grow at refrigeration temperaturesMost pathogens are mesophiles

21TemperatureOptimal GrowthThermophiles like hot conditionsMesophiles like warm conditions (around body temperature)Psychrotrophs can grow at refrigeration temperaturesMost pathogens are mesophiles

Lecture 321Temperature Classifications*Based on optimum temperature for growth; *Psychro=cold *Meso = middle *Thermo= warm *Trophic =growing *Duric=withstand *Phil or philic-prefers or loves

22Temperature Classifications

*Based on optimum temperature for growth; *Psychro=cold *Meso = middle *Thermo= warm *Trophic =growing *Duric=withstand *Phil or philic-prefers or loves

Lecture 322Categories of Microbes Based on Temperature Range

Image: Pearson Education Inc. (2004) publishing as Benjamin Cummings23Categories of Microbes Based on Temperature RangeLecture 924

Controlling GrowthTemperature Danger Zone

25The DANGER ZONELecture 325Controlling GrowthTemperature lower than 41FBacteria cease to multiply but do not dieFreezing can cause cell wall damageTemperature higher than 135 FBacteria die if heated for a sufficient timeIncreased destruction with longer times and higher temperatures

26THE DANGER ZONE EXPLANATION

Temperature lower than 41FBacteria cease to multiply but do not dieFreezing can cause cell wall damageTemperature higher than 135 FBacteria die if heated for a sufficient timeIncreased destruction with longer times and higher temperatures

Lecture 32627Controlling Growth TIMEUnder optimal conditions, some bacteria can double every 20 minutes.The colder the storage temperature, the longer the potential shelflife.Potentially hazardous foods should not remain in the danger zone (50-1400F) for more than 4 hours during the entire food handling process.27Conditions Affecting Bacterial Growth

TIMEUnder optimal conditions, some bacteria can double every 20 minutes.The colder the storage temperature, the longer the potential shelflife.Potentially hazardous foods should not remain in the danger zone (50-1400F) for more than 4 hours during the entire food handling process.Lecture 9Growth of Bacteria20 minutes40 minutesFour hoursUnder optimal conditions. ~500 million! 80 minutes28Binary Fission Lecture 328Generation Time Under Optimal Conditions (at 37oC)Organism Generation Time (min)

Bacillus cereus 28

Escherichia coli 12.5

Staphylococcus aureus (causes many infections: toxic shock syndrome one example) 27-30

Mycobacterium tuberculosis (agent of Tuberculosis) 792 932

29Generation Time Under Optimal Conditions (at 37oC)

Organism Generation Time (min)

Bacillus cereus 28

Escherichia coli 12.5

Staphylococcus aureus (causes many infections: toxic shock syndrome one example) 27-30

Mycobacterium tuberculosis (agent of Tuberculosis) 792 932

Lecture 9Bacterial Growth PhasesTimePopulationLag PhaseLog PhaseStationary PhaseDeath Phase30Bacterial Growth PhasesLag, log phase, stationary phase, death phaseLecture 330 O = OxygenBased on oxygen requirements; Aerobic-Need oxygen to grow Anaerobic-Can grow only if oxygen is absent Facultative-Can grow with or without oxygen.

31O = Oxygen

Based on oxygen requirements; Aerobic-Need oxygen to grow Anaerobic-Can grow only if oxygen is absent Facultative-Can grow with or without oxygen.

Lecture 331Controlling GrowthOxygenTolerance to oxygen in the surrounding environmentAnaerobicAerobicFacultative Anaerobes32OxygenTolerance to oxygen in the surrounding environmentLecture 332Controlling GrowthMoisture Water ActivityWater Activity (aw) is the measure of free water available to the microorganism for growth33Moisture Water ActivityWater Activity (aw) is the measure of free water available to the microorganism for growthLecture 333Water ActivityAw is affected by the presence of solutes (sugars and salts)

Lowering aw will reduce the ability for microorganisms to growSalt or Sugar34Water Activity

Aw is affected by the presence of solutes (sugars and salts)

Lowering aw will reduce the ability for microorganisms to grow

Lecture 334 35Moisture in a food system that is available for microbial growth and chemical reactions the relative humidity of a food

0.98 - 0.995 most foods.85 -.995 for disease causing organisms range .60 - .995 for spoilage organismsWater Activity

WATER ACTIVITY Aw/ Microorganism1.0-0.95 Bacteria

0.95-0.91 Bacteria

0.91-0.87 Yeasts

0.87-0.80 Molds

0.30-0.20 No microorganisms proliferate

FoodsMeat, fish, sausage, milk

Moist cheeses, cured meat (ham), fruit juice conc

Fermented sausages (salami), dry cheeses, margarineJuice conc, syrups, flour, fruit cakes, honey, jellies, preserves

Cookies, crackers, bread crusts

36WATER ACTIVITY Aw Microorganism FoodsLecture 336 37

Water Activity: Foods and Microbial GrowthControlling Growth0.50.751.0Water Activity of Common Foods

38Aw of certain foods Lecture 338Controlling GrowthSUMMARY:Microorganisms can grow on food and in the environment under the right conditionsRemember F-A-T-T-O-MFood, Acidity, Temperature, Time, Oxygen, and Moisture

39SUMMARY: re FATTOM Microorganisms can grow on food and in the environment under the right conditionsRemember F-A-T-T-O-MFood, Acidity, Temperature, Time, Oxygen, and MoistureLecture 339Interventions 40 41Interventions Combined Effects Hurdles ConceptPredictive microbiology The study of interactive effects of factors effecting microbial growthAdditive effects Synergistic effects Antagonistic effects

42Ingredients Have good specifications and control of incoming ingredients ProcessHave an adequate thermal process to destroy microorganismsHave an adequate packaging system to protect your product After ProcessingHave control of distribution and a system for tracking and recalling Provide necessary information for consumers (labeling)

Farm to Fork Food Safety and Quality ProgramsHACCP, GMPs, Sanitation

Food Industry Interventions 43 Specifications for ingredient make-up, quality, physical and microbial contaminant levels Letter of guarantee Certificate of analysis

Ingredient Control 44Thermal ProcessingCookingPasteurizationCommercial sterility (shelf-stable) processesRetort systems, aseptic processing, and hot filling

Package IntegrityMeasurements are made to insure the package is of good sanitary quality and can maintain a hermetic seal (such as visual inspections and torque measurements for your containers) Thermal Processing Control

45Thermal Processing ControlLow acid foods (pH>4.6, Aw>.85) Should have a process to eliminate 1,000,000,000,000 spores of Clostridium botulinum Examples: Most meat, vegetable, and dairy products Process often at 230oF or above (retorts, aseptic processing)

Acidified foods (pH altered to .85) Not required to have a process to eliminate Clostridium botulinum Examples: Pickled products, mayonnaise Process often 180 - 205oF (pasteurization, hot filling)

High acid foods (pH .85) Not required to have a heat process.Examples: sliced oranges, condimentsProcess often 180 - 205oF (pasteurization, hot filling)

46Pathogens General Roles of MicroorganismsCommensal ubiquitousharmless or beneficialSpoilageCause food to become inedible due to changes in color, flavor, odor, appearance or texture.Grow to high levels and break down food componentsCommensal organisms that have reached high populations (105-107 CFU/g)Different products have different spoilage flora

47General Roles of Microorganisms

Commensal ubiquitousharmless or beneficialSpoilageCause food to become inedible due to changes in color, flavor, odor, appearance or texture.Grow to high levels and break down food componentsCommensal organisms that have reached high populations (105-107 CFU/g)Different products have different spoilage flora

Lecture 347General Characteristics of MicroorganismsBeneficialUsed as an aid in producing desirable characteristics in foodPathogensCause foodborne illnessMicroorganisms that are usually associated with the presence of pathogens are called Indicators. Most E coli do not cause illness. 48General Characteristics of Microorganisms

BeneficialUsed as an aid in producing desirable characteristics in foodPathogensCause foodborne illnessMicroorganisms that are usually associated with the presence of pathogens are called Indicators

Lecture 348Food Safety vs. Food QualityFood safety controls HAZARDS to the consumer. A foodborne hazard is a biological, chemical, or physical property that may cause a food to be unsafe for human consumptionFood quality controls deterioration of food to an unacceptable state49Food Safety vs. Food Quality

Food safety controls HAZARDS to the consumer. A foodborne hazard is a biological, chemical, or physical property that may cause a food to be unsafe for human consumptionFood quality controls deterioration of food to an unacceptable stateLecture 349Foodborne IllnessFoodborne illness in the United States is associated with:46 million illnesses a year325,000 hospitalizations a year3,000 deaths a yearA loss of $10-83 billion in pain & suffering, reduced productivity, and medical costs50Foodborne IllnessFoodborne illness in the United States is associated with:46 million illnesses a year325,000 hospitalizations a year3,000 deaths a yearA loss of $10-83 billion in pain & suffering, reduced productivity, and medical costs

Lecture 350Common Foodborne PathogensE. coli 0157:H7Salmonella spp.Staphyloccus aureusListeria monocytogenesCampylobacter jejuniShigella spp.NorovirusRotovirusHepatitis ACryptosporidium parvumGiardia lambliaCyclospora

BacteriaVirusesParasites51Common Foodborne Pathogens

Lecture 35180-90% of Foodborne Illnesses from Bacteria come from just 4 Bacteria CampylobacterSalmonellaClostridium perfringensStaphylococcus aureus5280-90% of Foodborne Illnesses from Bacteria come from just 4 Bacteria

CampylobacterSalmonellaClostridium perfringensStaphylococcus aureus

52Lecture 17Illness MechanismsInfectionMicroorganisms are ingested and then cause illnessIntoxicationToxins are produced by the pathogen, usually in the food. When food is consumed, illness occurs.Even if microorganisms are killed, toxin can still remain the food53Illness Mechanisms

InfectionMicroorganisms are ingested and then cause illnessIntoxicationToxins are produced by the pathogen, usually in the food. When food is consumed, illness occurs.Even if microorganisms are killed, toxin can still remain the food

Lecture 353Bacterial Pathogens of ConcernE. coli O157:H7SalmonellaListeriaCampylobacterStaphylococcus aureusClostridium botulinum54Bacterial Pathogens of Concern

E. coli O157:H7SalmonellaListeriaCampylobacterStaphylococcus aureusClostridium botulinum

Lecture 354Which Bacteria are Responsible?

55Which Bacteria are Responsible?Lecture 355E. coli O157:H7Hemorrhagic colitisCause: infectionIncubation: 2-4 daysSymptoms: diarrhea (blood), HUS, TPPContaminant: milk, meat, fruits, vegetables, water

E. coli O157:H7

Hemorrhagic colitisCause: infectionIncubation: 2-4 daysSymptoms: diarrhea (blood), HUS, TPPContaminant: milk, meat, fruits, vegetables, waterLecture 356SalmonellaSalmonellosis>2000 strains, 10 = foodborne illnessCause: infectionIncubation: 6-48 hoursSymptoms: nausea, fever, diarrhea, arthritis Contaminant: milk, meat, eggs

Salmonella

Salmonellosis>2000 strains, 10 = foodborne illnessCause: infectionIncubation: 6-48 hoursSymptoms: nausea, fever, diarrhea, arthritis Contaminant: milk, meat, eggs

Lecture 357Listeria monocytogenesListeriosisCause: infectionIncubation: 2 days - 3 weeksSymptoms: vomiting, diarrheameningitis, septicemia, miscarriageContaminant: vegetables, milk, cheese, meat, seafood

Listeria monocytogenes

ListeriosisCause: infectionIncubation: 2 days - 3 weeksSymptoms: vomiting, diarrheameningitis, septicemia, miscarriageContaminant: vegetables, milk, cheese, meat, seafood

Lecture 358CampylobacterjejuniCampylobacteriosisCause: infectionIncubation: 2 - 5 daysSymptoms: nausea, fever, diarrhea (blood) Contaminant: milk, meat, water

Campylobacterjejuni

CampylobacteriosisCause: infectionIncubation: 2 - 5 daysSymptoms: nausea, fever, diarrhea (blood) Contaminant: milk, meat, water

Lecture 359StaphylococcusaureusStaphyloenterotoxicosisCause: intoxication(1 mg toxin = 100,000 cfu/g)Incubation: 1-6 hoursSymptoms: nausea, fever, diarrheaContaminant: milk, meat, eggs

Staphylococcusaureus

StaphyloenterotoxicosisCause: intoxication(1 mg toxin = 100,000 cfu/g)Incubation: 1-6 hoursSymptoms: nausea, fever, diarrheaContaminant: milk, meat, eggs

Lecture 360ClostridiumbotulinumBotulismCause: intoxication (spores - neurotoxin)Incubation: 18 -36 hoursSymptoms: weakness, vertigodifficulty in speaking, swallowing, breathingContaminant: pH >4.6, low oxygen foods

Clostridiumbotulinum

BotulismCause: intoxication (spores - neurotoxin)Incubation: 18 -36 hoursSymptoms: weakness, vertigodifficulty in speaking, swallowing, breathingContaminant: pH >4.6, low oxygen foods

Lecture 361Prevention of Foodborne Illness1)Cook- Cook all meat, poultry and eggs to at least 160F. Other than spore-forming bacteria, all bacteria, parasites and viruses are killed quite easily with heating to 160F.2)Avoid Cross-Contamination- Do not cross-contaminate one food with another. Keep raw food totally separated from cooked product. Clean utensils and work areas etc in between working raw and cooked product. Constantly be thinking of how microorganisms get from raw to cooked products.62Prevention of Foodborne Illness1)Cook- Cook all meat, poultry and eggs to at least 160F. Other than spore-forming bacteria, all bacteria, parasites and viruses are killed quite easily with heating to 160F.2)Avoid Cross-Contamination- Do not cross-contaminate one food with another. Keep raw food totally separated from cooked product. Clean utensils and work areas etc in between working raw and cooked product. Constantly be thinking of how microorganisms get from raw to cooked products.

62Lecture 17Prevention of Foodborne Illnesses3)Chill Foods- Keep foods cold. After cooking, chill foods as rapidly as possible. Remember that cooking has destroyed most of the bacteria but spore formers, that are resistant to cooking may become very active and can proliferate rapidly.4)Cleaning-Wash fruits and vegetables and all foods possible. In addition, continually wash work areas. Use only treated or tested water.63Prevention of Foodborne Illnesses3)Chill Foods- Keep foods cold. After cooking, chill foods as rapidly as possible. Remember that cooking has destroyed most of the bacteria but spore formers, that are resistant to cooking may become very active and can proliferate rapidly.4)Cleaning-Wash fruits and vegetables and all foods possible. In addition, continually wash work areas. Use only treated or tested water.

63Lecture 17Prevention of Foodborne Illnesses5)Personal Hygiene- People working with foods should wash their hands regularly, wear hairnets, plastic gloves etc. In addition, food handlers should not work with food if they have a boil, open sores or feel sick themselves64Prevention of Foodborne Illnesses

5)Personal Hygiene- People working with foods should wash their hands regularly, wear hairnets, plastic gloves etc. In addition, food handlers should not work with food if they have a boil, open sores or feel sick themselves

64Lecture 17Spoilage OrganismsBacterial (hundreds of bacteria cause spoilage) Erwinia, Pseudomonas, Flavobacteria, & Enterobacter spp.Lactic acid bacteria

FungalPenicillium, Aspergillus, Fusarium, and Candida

65Spoilage Organisms

BacterialErwinia, Pseudomonas, Flavobacteria, & Enterobacter spp.Lactic acid bacteria

FungalPenicillium, Aspergillus, Fusarium, and Candida

Lecture 365CONCLUSIONS Food Microbiology is huge areaFATTOM Pathogens Food SafetySpoilage microorganisms costly

66CONCLUSIONS

Food Microbiology is huge areaFATTOM Pathogens Food SafetySpoilage microorganisms costly

Lecture 366PathogenCasesDeaths

Campylobacter jejuni4,000,000200-1000

Salmonella2,000,000500-2000

Stapylococcus aureas 1,500,0001200

Escherichia coli O157:H7725,000100-200

Clostridium spp.10,000100

Listeria monocytogenes1500250-500